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Abstract:

A printed circuit board having a micro strip line, a printed circuit
board having a strip line and a method of manufacturing thereof are
disclosed. The printed circuit board having a micro strip line in
accordance with an embodiment of the present invention includes a first
insulation layer, a signal line buried in one surface of the first
insulation layer, a plurality of conductors penetrating through the first
insulation layer and being disposed on both sides of the signal line in
parallel with the signal line, and a ground layer formed to be
electrically connected to the conductor on the other surface of the first
insulation layer.

Claims:

1-10. (canceled)

11. A printed circuit board having a strip line, comprising: a first
insulation layer, a signal line being buried in one surface of the first
insulation layer; a plurality of conductors penetrating through the first
insulation layer and being disposed on both sides of the signal line in
parallel with the signal line; a ground layer formed on the other surface
of the insulation layer such that the ground layer is electrically
connected to the conductor; a second insulation layer formed on one
surface of the first insulation layer such that the second insulation
layer covers the signal line; and a power layer formed on the second
insulation layer.

12. The printed circuit board of claim 11, wherein there are a plurality
of the signal lines, and the signal line and the conductor are
alternately disposed.

13. The printed circuit board of claim 11, wherein the signal line is
constituted by a pair of unit signal lines, and the pair of unit signal
lines is a differential pair.

14. The printed circuit board of claim 11 wherein each distance between
the signal line and the conductors is identical to one another.

15. The printed circuit board of claim 11, wherein a side of the signal
line faces a side of the conductor in parallel.

16. The printed circuit board of claim 15, wherein the width of the
signal line becomes narrower toward farther the other surface of the
insulation layer.

17. A method of manufacturing a printed circuit board having a strip
line, the method comprising: forming a signal line on a carrier; burying
the signal line in one surface of a first insulation layer by pressing
the carrier onto the one surface of the first insulation layer; removing
the carrier; forming a plurality of conductors on the first insulation
layer such that the conductors penetrate through the first insulation
layer and are disposed on both sides of the signal line in parallel with
the signal line; forming a ground layer on the other surface of the first
insulation layer such that the ground layer is electrically connected to
the conductor; forming a second insulation layer on one surface of the
first insulation layer such that the second insulation layer covers the
signal line; and forming a power layer on the second insulation layer.

18. The method of claim 17, wherein the forming of the conductor
comprises: boring a through-hole in the first insulation layer; and
filling the through-hole with a conductive material.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a Divisional of U.S. application Ser. No.
12/361,781, filed Jan. 29, 2009, which claims the benefit of Korean
Patent Application No. 10-2008-0087265, filed with the Korean
Intellectual Property Office on Sep. 4, 2008, the disclosure of which is
incorporated herein by reference in its entirety.

BACKGROUND

[0002] 1. Technical Field

[0003] The present invention relates to a printed circuit board having a
micro strip line, and a printed circuit board having a strip line and a
method of manufacturing thereof.

[0004] 2. Description of the Related Art

[0005] High performance of a digital device is increasing the frequency of
the signal transmitted between semiconductor devices. Thus, a printed
circuit board having a structure of a micro strip line or a strip line is
now being used in order to transmit a high frequency signal.

[0006] FIG. 1 shows a printed circuit board 10 having a micro strip line
according to a conventional technology. FIG. 2 shows a printed circuit
board 20 having a strip line according to a conventional technology.

[0007] According to the conventional technology, as shown in FIG. 1, a
signal line 13 is formed on one surface of an insulation layer 11 and a
ground layer 12 is formed on the other surface of the insulation layer.
Otherwise, as shown in FIG. 2, a power layer 24 is formed on one surface
of the insulation layer 21 and the ground layer 22 is formed on the other
surface of the insulation layer 21. A signal line 23 is also buried in
the insulation layer 21 so that a digital signal is transmitted between
semiconductor devices.

[0008] However, the conventional technology has a limited maximum
bandwidth of a transmitted signal by causing cross talk between adjacent
signal lines 13 and 23, and signal transmission distortion, that is,
noise due to signal dispersion.

SUMMARY OF THE INVENTION

[0009] The present invention provides a printed circuit board having a
micro strip line and a printed circuit board having a strip line capable
of reducing both cross talk between signal lines and signal dispersion,
and a method of manufacturing thereof.

[0010] An aspect of the present invention features a printed circuit board
having a micro strip line. The printed circuit board in accordance with
an embodiment of the present invention can include: a first insulation
layer; a signal line buried in one surface of the first insulation layer;
a plurality of conductors penetrating through the first insulation layer
and being disposed on both sides of the signal line in parallel with the
signal line; and a ground layer formed to be electrically connected to
the conductor on the other surface of the first insulation layer.

[0011] There are a plurality of the signal lines, and the signal line and
the conductor can be alternately disposed.

[0012] The signal line can be constituted by a pair of unit signal lines,
and the pair of unit signal lines can be a differential pair.

[0013] Each distance between the signal line and the conductors is
identical to one another.

[0014] Meanwhile, a side of the signal line can face a side of the
conductor in parallel.

[0015] Also, the width of the signal line can become narrower toward a
farther surface of the insulation layer.

[0016] The printed circuit board can further include a second insulation
layer formed on the ground layer, and a power layer formed on the second
insulation layer.

[0017] Another aspect of the present invention features a method of
manufacturing a printed circuit board having a micro strip line. The
method in accordance with an embodiment of the present invention can
include: forming a signal line on a carrier; burying the signal line in
one surface of a first insulation layer by pressing the carrier onto the
one surface of the first insulation layer; forming a plurality of
conductors in the first insulation layer such that the conductors
penetrate through the first insulation layer and are disposed on both
sides of the signal line in parallel with the signal line; and forming a
ground layer on the other surface of the first insulation layer such that
the ground layer is electrically connected to the conductor.

[0018] Here, the forming of the conductor can include boring a
through-hole in the first insulation layer, and filling the through-hole
with a conductive material.

[0019] Also, after the forming of the ground layer, the method can further
include forming a second insulation layer on the ground layer, and
forming a power layer on the second insulation layer.

[0020] Yet another aspect of the present invention features a printed
circuit board having a strip line. The printed circuit board in
accordance with an embodiment of the present invention can include: a
first insulation layer, a signal line being buried in one surface of the
first insulation layer; a plurality of conductors penetrating through the
first insulation layer and being disposed on both sides of the signal
line in parallel with the signal line; a ground layer formed on the other
surface of the insulation layer such that the ground layer is
electrically connected to the conductor; a second insulation layer formed
on one surface of the first insulation layer such that the second
insulation layer covers the signal line; and a power layer formed on the
second insulation layer.

[0021] In this case, there are a plurality of the signal lines, and the
signal line and the conductor can be alternately disposed.

[0022] The signal line can be constituted by a pair of unit signal lines,
and the pair of unit signal lines can be a differential pair.

[0023] Each distance between the signal line and the conductors can be
identical to one another.

[0024] Meanwhile, a side of the signal line can face a side of the
conductor in parallel.

[0025] The width of the signal line becomes narrower toward farther the
other surface of the insulation layer.

[0026] Still another aspect of the present invention features a method of
manufacturing a printed circuit board having a strip line. The printed
circuit board in accordance with an embodiment of the present invention
can include: forming a signal line on a carrier; burying the signal line
in one surface of a first insulation layer by pressing the carrier onto
the one surface of the first insulation layer; removing the carrier;
forming a plurality of conductors on the first insulation layer such that
the conductors penetrate through the first insulation layer and are
disposed on both sides of the signal line in parallel with the signal
line; forming a ground layer on the other surface of the first insulation
layer such that the ground layer is electrically connected to the
conductor; forming a second insulation layer on one surface of the first
insulation layer such that the second insulation layer covers the signal
line; and forming a power layer on the second insulation layer.

[0027] In this case, the forming of the conductor can further include
boring a through-hole in the first insulation layer; and filling the
through-hole with a conductive material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a cross sectional view showing a printed circuit board
having a micro strip line according to a conventional technology.

[0029]FIG. 2 is a cross sectional view showing a printed circuit board
having a strip line according to a conventional technology.

[0030]FIG. 3 is a perspective view showing an embodiment of a printed
circuit board having a micro strip line according to an aspect of the
present invention.

[0031]FIG. 4 is a cross sectional view showing an embodiment of a printed
circuit board having a micro strip line according to an aspect of the
present invention.

[0032] FIGS. 5 to 8 are cross sectional views showing transformed shapes
of a printed circuit board having a micro strip line according to an
aspect of the present invention.

[0033]FIG. 9 is a flowchart showing an embodiment of a method of
manufacturing a printed circuit board having a micro strip line according
to another aspect of the present invention.

[0034] FIGS. 10 to 17 are cross sectional views showing processes of an
embodiment of a method of manufacturing a printed circuit board having a
micro strip line according to another aspect of the present invention.

[0035] FIG. 18 is a cross sectional view showing an embodiment of a
printed circuit board having a strip line according to yet another aspect
of the present invention.

[0036] FIGS. 19 to 21 are cross sectional views showing transformed shapes
of an embodiment of a printed circuit board having a strip line according
to yet another aspect of the present invention

[0037] FIG. 22 is a flowchart showing an embodiment of a method of
manufacturing a printed circuit board having a strip line according to
still another aspect of the present invention.

[0038] FIGS. 23 to 30 are cross sectional views showing processes of an
embodiment of a method of manufacturing a printed circuit board having a
strip line according to still another aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0039] A printed circuit board having a micro strip line according to the
present invention, a printed circuit board having a strip line and a
method of manufacturing thereof will be described in detail with
reference to the accompanying drawings. In description with reference to
the accompanying drawings, the same reference numerals will be assigned
to the same or corresponding element, and repetitive description thereof
will be omitted.

[0040]FIG. 3 is a perspective view showing an embodiment of a printed
circuit board 100 having a micro strip line according to an aspect of the
present invention. FIG. 4 is a cross sectional view showing an embodiment
of a printed circuit board 100 having a micro strip line according to an
aspect of the present invention.

[0041] According to the embodiment of the present invention, provided is a
printed circuit board 100 having a micro strip line. The printed circuit
board includes a first insulation layer 110, a signal line 120 buried in
one surface of the first insulation layer 110, a plurality of conductors
130 penetrating through the first insulation layer 110 and being disposed
on both sides of the signal line 120 in parallel with the signal line
120, and a ground layer 140 formed on the other surface of the first
insulation layer 110 such that the ground layer is electrically connected
to the conductor 130.

[0042] According to such an embodiment of the present invention, cross
talk between adjacent signal lines 120 and digital signal distortion
caused by inductance difference between a high frequency signal and a low
frequency signal, that is, signal dispersion are reduced. Consequently,
the transmission quality of a high-speed digital signal can be improved.

[0043] Hereinafter, structures of the embodiment of the present invention
will be described in more detail with reference to FIGS. 3 to 8.

[0044] The micro strip line structure according to the embodiment of the
present invention is constituted by the signal line 120, the ground layer
140, the first insulation layer 110 interposed between the signal line
and the ground layer, and the conductor 130 disposed on both sides of the
signal line 120.

[0045] The signal line 120 is buried in one surface of the first
insulation layer 110 and a plurality of the signal lines can be formed at
a predetermined interval. An alternating current flows through the signal
line 120. Cross talk may be created by coupling capacitance formed
between adjacent signal lines 120. Such a cross talk can be reduced by
blocking the space between the signal lines 120 by means of the conductor
130 to be described below. This matter will be described in more detail
in description of the conductor 130.

[0046] Additionally, the ground layer 140 is formed on the other surface
of the first insulation layer 110 such that the ground layer is
electrically connected to the conductor 130 to be described below. In
this case, a part of the ground layer 140 can be used as a current path.
This matter will be described in more detail in description of the
conductor 130.

[0047] A plurality of the conductors 130 penetrate through the first
insulation layer 110 and are disposed on both sides of the signal line
120 in parallel with the signal line 120. In other words, since the
conductor 130 is formed to penetrate through one and the other surfaces
of the first insulation layer 110 and since a pair of the conductors 130
disposed on both sides of the signal line 120 on the basis thereof is
formed in parallel with the preceding direction of the current in the
signal line 120, the signal line 120 is surrounded by both a pair of the
conductors 130 disposed on both sides thereof and the ground layer 140.

[0048] Accordingly, with a minimal change of the current path in the
ground layer 140 in accordance with the frequency change of the
alternating current being transmitted to the ground layer 140, the
distortion of digital signal transfer caused by inductance difference
between a high frequency signal and a low frequency signal, that is,
signal dispersion can be reduced. This matter will be described in more
detain in comparison with a conventional technology.

[0049] According to a conventional technology, due to both a skin effect,
i.e., a phenomenon in which a high frequency current flows only around
the surface of a conductor and a proximity effect, i.e., a phenomenon in
which a high frequency current more concentrically flows through a part
close to other conductor, the ground layer 140 has the current path of
the high frequency current flow which becomes narrower than that of the
low frequency current.

[0050] As a result, the high frequency current has a inductance lower than
that of the low frequency current and the transfer speed of the
alternating current changes according to the a frequency. Consequently,
signal dispersion in which a digital signal being transmitted is
distorted occurs.

[0051] However, according to the embodiment of the present invention,
since the signal line 120 is surrounded by the conductor 130 and the
ground layer 140, not only the ground layer 140 but also the side of the
conductor 130 adjacent to the signal line 120 is used as the current
path.

[0052] That is, the conductor 130 is formed at a distance similar to a
distance from the signal line 120 to the ground layer 140, so that the
side of the conductor 130 as well as the ground layer 140 can be used as
a current path, when not only does the low frequency current flow, but
also the high frequency current flows through the ground layer 140.

[0053] As such, with a minimal change of the current path according to the
frequency, the dispersion mentioned above can be remarkably reduced.

[0054] Since a resistance can be minimized by using not only the ground
layer 140 but also the side of the conductor 130 as a current path in the
high frequency, the quality of the digital signal being transmitted can
be more improved.

[0055] Here, as shown in FIG. 4, each distance d1 and d2 between the
signal line 120 and the conductors is identical to one another.
Therefore, the current path mentioned above is symmetrical, so that noise
can be reduced. Consequently, the quality of the digital signal being
transmitted can be more improved.

[0056] Meanwhile, there are a plurality of the signal lines 120. The
signal line 120 and the conductor 130 are alternately disposed. Because
the conductor 130 performs a function of an obstruction, cross talk
between the adjacent signal lines 120 can be reduced.

[0057] That is, the signal line 120 is completely buried in the first
insulation layer 110. The conductor 130 penetrates through the first
insulation layer 110 and is formed across both surfaces of the first
insulation layer 110. Finally, the adjacent signal lines 120 are entirely
blocked by the conductor 130.

[0058] With respect to the adjacent signal lines 120, cross talk is
created by coupling capacitance generated between the adjacent signal
lines, so that noise may occur in the digital signal being transmitted.
In order to prevent said problem, in the embodiment of the present
invention, a capacitance is prevented from being formed between the
adjacent lines 120 by disposing the conductor 130 which blocks the space
between a plurality of the signal lines 120. Accordingly, cross talk
caused by the capacitor can be notably reduced.

[0059] Next, a transformed shape of the embodiment of the present
invention will be described with reference to FIGS. 5 to 8 focusing on a
difference from the description above.

[0060] FIGS. 5 to 8 are cross sectional views showing transformed shapes
of a printed circuit board 100 having a micro strip line according to an
aspect of the present invention.

[0061] In FIG. 5, a signal line 120 can be constituted by a pair of unit
signal lines 122 and 124. Such unit signal lines 122 and 124 can be a
differential pair. As a result, even though an alternating current
transmitted to one unit signal line 122 is changed due to noise, the
other unit signal line 124 compensates for the change due to noise.
Eventually, the quality of the digital signal being transmitted can be
improved.

[0062] Besides, in FIG. 6, the side of the signal line 120 faces the side
of the conductor 130 in parallel. The width of the signal line 120
becomes narrower toward the other surface of the insulation layer, such
that the cross-section of the signal line 120 can have a trapezoidal
shape. As the side of the signal line 120 faces the side of the conductor
130 in parallel, a certain distance between the signal line and the
conductor can be maintained. Accordingly, the occurrence of noise can be
reduced and a high-quality digital signal can be more efficiently
transmitted.

[0063] As shown in FIG. 6, the side of the signal line 120 faces the side
of the conductor 130 in parallel as well as the width of the lower part
of the signal line 120 is narrower than that of the upper part of the
signal line. Thus, a distance from each point of the surface of the
signal line 120 to both the ground layer 140 and the conductor 130 can be
relatively and uniformly maintained. Accordingly, the occurrence of noise
can be reduced and a digital signal can be more efficiently transmitted.

[0064] In this case, as shown in FIG. 6, the width of the conductor 130
becomes narrower toward the upper part from the lower part. As a result,
since one surface of the first insulation layer 110 has an increasing
space, the degree of density of the signal line 120 buried in one surface
of the first insulation layer 110 can be increased.

[0065] In FIG. 7, shown are a signal line 120 having a trapezoidal
cross-section and unit signal lines 122 and 124 being a differential
pair. The detailed description thereof will be omitted.

[0066] As shown in FIG. 8, the printed circuit board 100 according to the
embodiment of the present invention can further include a second
insulation layer 150 formed on the ground layer 140 and a power layer 160
formed on the second insulation layer 150.

[0067] Next, an embodiment of a method of manufacturing a printed circuit
board 200 having a micro strip line according to another aspect of the
present invention will be described.

[0068]FIG. 9 is a flowchart showing an embodiment of a method of
manufacturing a printed circuit board having a micro strip line according
to another aspect of the present invention. FIGS. 10 to 17 are cross
sectional views showing processes of an embodiment of a method of
manufacturing a printed circuit board 200 having a micro strip line
according to another aspect of the present invention.

[0069] According to the embodiment of the present invention, provided is a
method of manufacturing a printed circuit board 200 having a micro strip
line. The method includes forming a signal line 220 on a carrier 205 (see
FIG. 10), burying the signal line 220 in one surface of a first
insulation layer 210 by pressing the carrier 205 onto the one surface of
the first insulation layer 210 (see FIG. 11), forming a plurality of
conductors 230 in the first insulation layer 210 such that the conductors
penetrate through the first insulation layer 210 and are disposed on both
sides of the signal line 220 in parallel with the signal line 220 (see
FIG. 14), and forming a ground layer 240 on the other surface of the
first insulation layer 210 such that the ground layer is electrically
connected to the conductor 230 (see FIG. 15).

[0070] According to such an embodiment of the present invention, it is
possible to implement the printed circuit board 200 reducing cross talk
between adjacent signal lines 220 and digital signal distortion caused by
inductance difference between a high frequency signal and a low frequency
signal, that is, signal dispersion.

[0071] Hereinafter, each process will be described in detail with
reference to FIGS. 9 to 17.

[0072] First, as shown in FIG. 10, the signal line 220 is formed on the
carrier 205 (S110 in FIG. 9). For example, the signal line 220 is formed
on the carrier 205 by using electrolytic plating. In addition, the signal
line 220 can be also formed by using various processes such as a
subtractive process, an inkjet process and the like.

[0073] Subsequently, as shown in FIG. 11, the signal line 222 is buried in
one surface of the first insulation layer 210 by pressing the carrier 205
onto the one surface of the first insulation layer 210 (S120 in FIG. 9).
This is a process of heating and compressing the carrier 205 and the
first insulation layer 210 in order to bury the signal line 220 in one
surface of the first insulation layer 210. By using the carrier 205
mentioned above, it is possible to more easily bury the signal line 220
in the first insulation layer 210 and to enhance the adhesive strength
between the signal line 220 and the first insulation layer 210.

[0074] As shown in FIG. 12, the carrier 205 is removed from the one
surface of the first insulation layer 210 (S130 in FIG. 9). This is a
process of exposing the signal line 220 to the outside of the printed
circuit board 200. The signal line can be exposed by separating the
carrier 205 or by etching and removing the carrier.

[0075] As shown FIGS. 13 and 14, a plurality of the conductors 230 (see
FIG. 14) are formed in the first insulation layer 210 such that the
conductors penetrate through the first insulation layer 210 and are
disposed on both sides of the signal line 220 (see FIG. 14) in parallel
with the signal line 220 (S140 in FIG. 9). Here, the conductors 230 are
disposed on both sides of the signal line 220 and are extended in
parallel with the current proceeding direction of the signal line 220, so
that the conductor surrounds the signal line 220 together with the ground
layer 240. The conductor 230 is disposed in the space between a plurality
of the signal lines 220 and blocks the space between the signal lines
220. As a result, the conductor 230 can reduce the signal dispersion and
cross talk. As the one embodiment mentioned above has described the
subject, the more detailed description thereof will be omitted.

[0076] The process of forming the conductor 230 mentioned above can be
described as below stage by stage.

[0077] First, as shown in FIG. 13, a through-hole 232 is bored in the
first insulation layer 210 (S142 in FIG. 9). In other words, the
through-hole 232 is bored in the first insulation layer 210 such that the
signal line 220 can be disposed between the conductors 230. Subsequently,
as shown in FIG. 14, the through-hole 232 is filled with a conductive
material (S144 in FIG. 9). For example, the through-hole can be filled by
plating the inside of the through-hole 232 or by filling the inside of
the through-hole 232 with a conductive paste.

[0078] As shown in FIG. 15, the ground layer 240 is formed on the other
surface of the first insulation layer 210 such that the ground layer is
electrically connected to the conductor 230 (S150 in FIG. 9). For
example, the ground layer can be formed by plating the other surface of
the first insulation layer 210 or by laminating copper foil on the other
surface of the first insulation layer.

[0079] In such a ground layer 240, a part of the ground layer is used as a
current path. The conductor 230 mentioned above is electrically connected
to the ground layer 240 so that the conductor as well as the ground layer
240 can be also used as a current path.

[0080] As shown in FIG. 16, a second insulation layer 250 is formed on the
ground layer 240 (S160 in FIG. 9). This is a process of forming the
second insulation layer 250 on the ground layer 240 which has been formed
in the previous process. For example, the process can be performed by
laminating the second insulation layer 250 on the ground layer 240.

[0081] As shown in FIG. 17, a power layer 260 is formed on the second
insulation layer 250 (S170 in FIG. 9). This is a process of forming the
power layer 260. For example, the power layer 260 can be formed by
plating the other surface of the second insulation layer 250 or by
laminating copper foil on the second insulation layer 250.

[0082] In the embodiment of the present invention, it has been provided as
an example that a method of performing a process S140 (in FIG. 9) of
forming a plurality of the conductors 230 in the first insulation layer
210 after performing the process 5120 (in FIG. 9) of burying the signal
line 220 on one surface of the first insulation layer 210. However, on
the contrary, the process S120 (in FIG. 9) of burying the signal line 220
can be performed after performing the process S140 (in FIG. 9) of forming
a plurality of the conductors 230, which also belongs to the scope of
rights of the present invention.

[0083] In the mean time, as shown in FIGS. 3 to 7, it is possible to
manufacture a printed circuit board (see reference numeral 100 in FIGS. 3
to 7) having various types of micro strip lines. Since a process of
manufacturing the printed circuit board is the same as or similar to that
of the embodiment of the present invention, descriptions thereof will be
omitted.

[0084] Next, an embodiment of a printed circuit board 300 having a strip
line according to yet another aspect of the present invention will be
described.

[0085] FIG. 18 is a cross sectional view showing an embodiment of a
printed circuit board 300 having a strip line according to yet another
aspect of the present invention. FIGS. 19 to 21 are cross sectional views
showing transformed shapes of an embodiment of a printed circuit board
300 having a strip line according to yet another aspect of the present
invention

[0086] According to the embodiment of the present invention, as shown in
FIG. 18, provided is a printed circuit board 300 having a strip line. The
printed circuit board includes a first insulation layer 310, a signal
line 320 buried in one surface of the first insulation layer 310, a
plurality of conductors 330 penetrating through the first insulation
layer 310 and being disposed on both sides of the signal line 320 in
parallel with the signal line 320, a ground layer 340 formed on the other
surface of the first insulation layer 310 such that the ground layer is
electrically connected to the conductor 330, a second insulation layer
350 formed on one surface of the first insulation layer 310 such that the
second insulation layer covers the signal line 320, and a power layer 360
formed on the second insulation layer 350.

[0087] According to such an embodiment of the present invention, cross
talk between adjacent signal lines 120 and digital signal distortion
caused by inductance difference between a high frequency signal and a low
frequency signal, that is, signal dispersion are reduced. Consequently,
the transmission quality of a high-speed digital signal can be improved.

[0088] In the embodiment of the present invention, since the configuration
and consequent functions of the first insulation layer 310, the signal
line 320, the unit signal lines 322 and 324, the conductor 330 and the
ground layer 340 have been described in the one embodiment of the printed
circuit board (see reference numeral 100 in FIGS. 3 to 7) having the
micro strip line described above, descriptions thereof will be omitted.
Hereinafter, a difference from the embodiment of the present invention,
that is, the second insulation layer 350 and the power layer 360 will be
described.

[0089] The second insulation layer 350 is formed on one surface of the
first insulation layer 310 such that the second insulation layer covers
the signal line 320. The power layer 360 is formed on such a second
insulation layer 350. Therefore, it is possible to form a strip line
structure having the signal line 320 buried between the first insulation
layer 310 and the second insulation layer 350, the ground layer 340
formed on the other surface of the first insulation layer 310, and the
power layer 360 formed on the second insulation layer 350.

[0090] Next, an embodiment of a method of manufacturing a printed circuit
board 400 having a strip line according to still another aspect of the
present invention will be described.

[0091] FIG. 22 is a flowchart showing an embodiment of a method of
manufacturing a printed circuit board having a strip line according to
still another aspect of the present invention. FIGS. 23 to 30 are cross
sectional views showing processes of an embodiment of a method of
manufacturing a printed circuit board having a strip line according to
still another aspect of the present invention.

[0092] According to the embodiment of the present invention, provided is a
method of manufacturing a printed circuit board 400 having a strip line.
The method includes forming a signal line 420 on a carrier 405 (see FIG.
23), forming a plurality of conductors 430 (see FIG. 25) on a first
insulation layer 410 (see FIG. 24) such that the conductors penetrate
through the first insulation layer 410 and are disposed on both sides of
the signal line 420 in parallel with the signal line 420, burying the
signal line 420 in one surface of a first insulation layer 410 by
pressing the carrier 405 onto the one surface of the first insulation
layer 410, removing the carrier 405, forming a ground layer 440 on the
other surface of the first insulation layer 410 such that the ground
layer is electrically connected to the conductor 430, forming a second
insulation layer 450 on one surface of the first insulation layer 410
such that the second insulation layer covers the signal line 420, and
forming a power layer 460 on the second insulation layer 450.

[0093] According to such an embodiment of the present invention, it is
possible to implement the printed circuit board 400 reducing cross talk
between adjacent signal lines 420 and digital signal distortion caused by
inductance difference between a high frequency signal and a low frequency
signal, that is, signal dispersion.

[0094] In the embodiment of the present invention, since the one
embodiment of the method of manufacturing the printed circuit board 400
(see reference numeral 200 of FIG. 17) having the strip line mentioned
above has described the process 5210 (in FIG. 22) of forming the signal
line 420 on the carrier 405 as shown in FIG. 23, the process S220 (in
FIG. 22) of forming a plurality of conductors 430 in the first insulation
layer 410 by boring a through-hole 432 in the first insulation layer 410
(S222 in FIG. 22) as shown in FIG. 24 and by filling the through-hole 432
(in FIG. 24) with the conductors 430 of a conductive material (S224 in
FIG. 22) as shown in FIG. 25, the process 5230 (in FIG. 22) of burying
the signal line 420 in one surface of the first insulation layer 410 as
shown in FIG. 26, the process 5240 (in FIG. 22) of removing the carrier
405 from the one surface of the first insulation layer 410 as shown in
FIG. 27, and the process 5250 (in FIG. 22) of forming the ground layer
440 on the other surface of the first insulation layer 410 as shown in
FIG. 28, descriptions thereof will be omitted. Hereinafter, differences
from the embodiment of the present invention, that is, a process 5260 (in
FIG. 22) of forming the second insulation layer 450 and a process 5270
(in FIG. 22) of forming the power layer 460 will be described.

[0095] After forming the ground layer 440, as shown in FIG. 29, the second
insulation layer 450 is formed on one surface of the first insulation
layer 410 such that the second insulation layer covers the signal line
420 (S260 in FIG. 22). This is a process of forming the second insulation
layer 450 to cover the signal line 420 in order to completely bury the
signal line 420. For example, the process can be performed by laminating
a semi-cured second insulation layer 450 on one surface of the first
insulation layer 410.

[0096] Next, as shown in FIG. 30, the power layer 460 is formed on the
second insulation layer 450 (S270 in FIG. 22). This is a process of
completing a strip line structure by forming the power layer 460 on the
second insulation layer 450. For example, the power layer 460 can be
formed by plating the second insulation layer 450 or by laminating copper
foil on the second insulation layer 450.

[0097] In the embodiment of the present invention, it has been provided as
an example that a method of performing a process 5230 (in FIG. 22) of
burying the signal line 420 on one surface of the first insulation layer
410 after performing a process 5220 (in FIG. 22) of forming a plurality
of the conductors 430 on the first insulation layer 410. However, on the
contrary, the process 5220 (in FIG. 22) of forming a plurality of the
conductors 430 can be performed after the process 5230 (of FIG. 22) of
burying the signal line 420, which also belongs to the scope of rights of
the present invention.

[0098] In the mean time, as shown in FIGS. 19 to 21, it is possible to
manufacture a printed circuit board (see reference numeral 300 in FIGS.
19 to 21) having various types of micro strip lines. Since a process of
manufacturing the printed circuit board is the same as or similar to that
of the embodiment of the present invention, descriptions thereof will be
omitted.

[0099] While the one embodiment of the present invention has been
described, it is possible for those skilled in the art to make various
changes and modifications of the forms and details of the present
invention by means of addition, change, elimination or supplement, etc.,
of the components of the present invention without departing from the
spirit of the present invention as defined by the appended claims, which
also belongs to the scope of rights of the present invention.